Wireless systems are evolving from the existing digital systems to new standards and equipment in order to provide new services. These services involve fast packet data services and such additional services as offering an “always connected” mode to an IP network for mobile subscribers. In particular a new third generation of mobile phones are being designed with fast internet connections. Some pre third generation systems also provide the internet connections.
Mobile phone services are becoming nation wide and extend over a wide area. These services may range across video, instant messaging, music service, stock market prices and trades, e-commerce, traffic guidance as well as many other IP type services. Extending these features to a wide area often requires the integration of service across many different networks. ATM networks have desirable characteristics that may be used to provide this integration.
ATM (Asynchronous Transfer Mode) is becoming a well-established transport medium within the telecommunications network. In ATM, individual packets (i.e., cells) are presented to the network asynchronously. Its rising popularity is due to its high speed; a critical ability for data transport and various media applications. It is characterized by high bandwidth, low delay, and packet (i.e., cell) switching capability. Ability to maintain a defined QoS (Quality of Service) is one major advantage of ATM. However, the fixed length of packets (i.e. cells) in ATM networks conflicts with packets generally used in other networks that have variable packet lengths.
Providing high-speed data service allowing transfer of information (i.e., sending and receiving), as noted above, is becoming an important feature of newly emerging wireless communication systems (i.e., cellular/PCS networks). System speed as well as QoS is important. Because voice, data and multimedia are readily accommodated by ATM, it appears to be a valuable transport medium for providing network transport between wireless systems providing such services. It becomes desirable to integrate the ATM network with the wireless network or networks providing these services. However, for many reasons, including its fixed packet lengths and the lack of the mobility functionality, the existing ATM network is not quite suited to be integrated with wireless networks that use Frame Relay packets of a variable and much longer length.
One new proposed wireless system with packet data capability is the General Packet Radio Service (GPRS) allowing fast packet data connections as indicated above and in which the mobile unit is in an “always connected” mode. This system is anticipated to be operational in advance of the new proposed 3G network. GPRS is a network that enables connections of subscriber equipment to a data network (i.e., Internet). It permits ready access of subscribers to external IP-based networks. It however uses frame relay packets that are not directly compatible with ATM networks.
In order to achieve these benefits and services it is necessary to provide network architecture to achieve integration of GPRS and like networks with other networks (i.e., such as ATM networks) using different structured packets for information transmission. In order to fully enjoy the benefits of the new available services provided by such integration, the network architecture should support such functions as call processing including signaling communication, feature applications, and provide for handoff functions and personal mobility management whereby mobile subscribers may connect to other wired subscribers and mobile subscribers through the integrating network.